Series of related transactions

"Series of related transactions" is an aggregation trigger that treats claims as a single claim where they arise from the same or similar acts or omissions occurring across a sequence of transactions that have an intrinsic relationship with one another.

Definition §

A "series of related transactions" is a defined unifying factor for aggregation in liability insurance, most prominently used in the SRA Minimum Terms and Conditions of Professional Indemnity Insurance (MTC). A "transaction" in this context describes a discrete commercial dealing — a sale, a purchase, an investment, a settlement, a transfer of property — which is the subject of professional advice. A series of related transactions is a sequence of such dealings which share a relevant connection. ^[1]

The trigger usually appears as part of a composite aggregation clause that combines four limbs. The relevant limb deems claims to be a single claim where they arise from similar acts or omissions in a series of related matters or transactions where there is a connection between them. The drafting reflects the regulator's policy choice that minor differences in the precise misconduct across a connected sequence of deals should not defeat aggregation, provided the underlying transactions are themselves related. ^[2]

The question of what makes transactions "related" was the central issue in AIG Europe Ltd v Woodman [2017] UKSC 18. The Supreme Court held that the relationship must be intrinsic — that is, internal to the transactions themselves — and not merely an extrinsic relationship arising from a shared external factor such as the same lawyer, the same client or the same kind of subject matter. ^[3]

Legal / Regulatory basis §

AIG Europe Ltd v Woodman [2017] UKSC 18 is the definitive English authority. The case concerned losses suffered by investors in two related property development schemes in Turkey and Morocco. Investor funds had been paid into escrow accounts held by a firm of solicitors and released in breach of the conditions of release. When the schemes failed, the investors brought professional negligence claims against the solicitors. The solicitors' AIG-led professional indemnity insurers sought to aggregate the claims under the SRA Minimum Terms wording referring to similar acts or omissions in a series of related transactions. ^[4]

The first instance judge had held that the transactions were not related. The Court of Appeal had held that to be related the transactions had to be dependent on one another in the sense that one had to complete in order for the other to do so. The Supreme Court rejected the Court of Appeal's narrower test. Lord Toulson, giving the judgment of the Court, held that the relationship must be intrinsic but need not be one of dependence in the strict sense identified by the Court of Appeal. The transactions in the AIG case, which formed parts of a single coherent scheme to develop and sell off plots in defined developments, were sufficiently related to engage the aggregation clause and the matter was remitted for further consideration on the facts. ^[5]

The Supreme Court's decision corrected the law in two directions at once. It confirmed that "related" does require a real connection and is not satisfied by a generic similarity, but it also confirmed that the connection need not be as tight as the Court of Appeal had suggested. The judgment is now the starting point for all aggregation analysis under SRA Minimum Terms wordings and is regularly cited in open market professional indemnity disputes as well. ^[6]

The Commercial Court applied AIG v Woodman shortly after the Supreme Court's decision in Cultural Foundation v Beazley Furlonge Ltd [2018] EWHC 1083 (Comm), which provides a worked example of the intrinsic-relationship test in practice. ^[7]

Earlier authorities continue to inform the analysis. Countrywide Assured Group plc v Marshall [2002] EWHC 2082 (Comm) considered the related transactions concept in an IFA mis-selling context and Standard Life Assurance Ltd v Oak Dedicated Ltd [2008] EWHC 222 (Comm) is a further pre-AIG application. ^[8]

The general principles of policy construction set out in Axa Reinsurance (UK) plc v Field [1996] 1 WLR 1026 — in particular the distinction between events and causes — also frame the analysis, even though that case did not concern the related transactions wording directly. ^[9]

How it works in practice §

Aggregation analysis under the related transactions trigger usually proceeds in three steps.

The first step identifies the candidate transactions. The court or claims handler must form a clear factual picture of each commercial dealing said to form part of the series. In the AIG case those were investments in particular property developments; in other cases they may be share sales, loan agreements or settlements.

The second step asks whether the relevant acts or omissions are the same or similar across the transactions. The composite SRA wording engages on similarity, not identity, but the underlying mistake must be recognisably the same kind of mistake in each. A defective standard document, a flawed advisory template or a repeated misapplication of a particular point of law typically satisfies this requirement.

The third and most contentious step asks whether the transactions are intrinsically related. After AIG v Woodman, the relevant question is whether the transactions have a real internal connection — for example because they are component parts of a single overall scheme, because they are dependent on one another in some practical sense, or because they share a unifying commercial purpose that ties them together. The mere fact that they involve the same lawyer, the same client or the same kind of transaction is not enough. ^[10]

The financial consequences of a positive finding are familiar: a single per-claim limit and a single excess apply to the whole series. In SRA MTC policies, which often have no aggregate limit on the primary layer, this can be significant in either direction depending on how the figures fall.

Common variations §

The trigger appears in slightly different forms in different wordings. The SRA Minimum Terms wording combines two limbs: the same act or omission in a series of related matters or transactions, and similar acts or omissions in a series of related matters or transactions where there is a connection between them. Open market PI policies sometimes simplify the wording or replace it with a broader originating cause trigger.

RICS minimum policy wording for chartered surveyors uses analogous concepts. Architects', engineers' and accountants' open market wordings also commonly include a related transactions trigger, often alongside a related matters trigger and an originating cause trigger.

Some wordings impose a temporal restriction, limiting the series to transactions occurring within a defined period. This is more common in financial services PI wordings than in solicitors' PI wordings.

Example §

A solicitors' firm advises a property developer on a scheme to sell off thirty plots in a single development to investors. The firm prepares a template investment agreement which, on a single point, fails to protect the investors' deposits as the marketing material had promised. Each of thirty investors enters into the template agreement and each later suffers loss when the development is not completed.

The firm's professional indemnity policy is written on SRA Minimum Terms with illustrative limits of £3,000,000 per claim and a £25,000 per-claim excess.

The aggregation analysis proceeds as follows. The thirty plot sales are candidate transactions. The same or similar act or omission — use of the defective template — runs through the series. The question is whether the transactions are intrinsically related. Because all thirty sales were component parts of a single development scheme, marketed and sold as a unit, the intrinsic-relationship test from AIG v Woodman is likely to be satisfied. The claims would aggregate to a single £3,000,000 limit with one £25,000 excess.

If the same firm had given similar advice on unconnected plots in unconnected developments for unconnected sellers, the intrinsic relationship between the transactions would be much harder to establish and the claims would be more likely to remain separate.

These figures are illustrative; the actual outcome depends on the wording and the facts.

See also §

• /wiki/aggregation-clause/ — the mechanism in which this trigger sits
• /wiki/series-of-related-matters/ — closely related SRA MTC trigger
• /wiki/originating-cause/ — broader unifying factor
• /wiki/single-act-or-omission/ — narrower SRA MTC trigger
• /wiki/per-claim-limit/ — financial control that aggregation engages
• /wiki/professional-indemnity-insurance/ — the line of business
• /wiki/solicitors-indemnity-fund/ — historical context for solicitors' PI

References §

1. ↑ AIG Europe Ltd v Woodman [2017] UKSC 18 — https://www.supremecourt.uk/cases/uksc-2016-0033.html
2. ↑ SRA Minimum Terms and Conditions of Professional Indemnity Insurance — https://www.sra.org.uk/solicitors/standards-regulations/indemnity-insurance-rules/
3. ↑ Cultural Foundation v Beazley Furlonge Ltd [2018] EWHC 1083 (Comm)
4. ↑ Countrywide Assured Group plc v Marshall [2002] EWHC 2082 (Comm)
5. ↑ Standard Life Assurance Ltd v Oak Dedicated Ltd [2008] EWHC 222 (Comm)
6. ↑ Axa Reinsurance (UK) plc v Field [1996] 1 WLR 1026 (HL)
7. ↑ Spire Healthcare Ltd v Royal & Sun Alliance Insurance plc [2022] EWCA Civ 17 — https://www.bailii.org/ew/cases/EWCA/Civ/2022/17.html
8. ↑ Insurance Act 2015 — https://www.legislation.gov.uk/ukpga/2015/4